Apparatus for dressing grinding wheels



Dec. 27, 1949 E. F. WHITE 2,492,722

APPARATUS FOR DRESSING GRINDING WHEELS Filed May 2, 1946 3 Shets-Sheet l Dec. 27, 1949 E. F. WHITE APPARATUS FOR DRESSING GRINDING WHEELS 3 Sheets-Sheet 2 Filed May 2, 1946 Dec. 27, 1949 E. F. WHITE APPARATUS FOR DRESSING GRINDING WHEELS Filed May 2, 1946 5 Sheets-Sheet 3 upon the finished workpiece.

Patented Dec. 27, 1949 UNITED STATES PATENT OFFICE" APPARATUS FOR DRESSING GRINDING WHEELS Ezekiel FieldWhite, West Hartford, Conn.

Application May 2, 1946, Serial No. 666,713

16 Claims. (01. 12511) This invention relates to an apparatus for dressing grinding wheels, and more particularly to the dressing of a grinding Wheel, the surfaces of which are not all parallel to'each other, so

that certain areas or zones upon the wheelstand at an angle to other or others of the areas or zones upon the wheel.

In grinding operations, it has been the custom, particularly in grinding small work, to advance the work against a rotating grinding wheel, the surface of which is complemental to that desired Thus, if the surface of the work is irregular in shape, the surface shape so that all of the areas on the workpiece would be properly ground by the Wheel in one operation.

It has been necessary to keep the surface of the grinding wheel truly and accurately dressed in order to perform accurate grinding upon the work, and it has usually been necessary to redress the wheel after a certain number of opera tions owing to the Wear upon its surface. Thisdressing operation has usually been performed by traversing a cutting tool, such as a diamond, over the surface of the wheel and controlling the tool So that it will generally follow the outline of the surface desired upon the wheel. -This method has the disadvantage, however, that, while it may produce fairly accurate results when the diamond cutter is sharp, it will not produce such results when the latter is dull, and this is particularly true when the work, and, therefore, the wheel, is provided with cylindrical and frusto-conical portions or areas, the conical portions lying at an angle to the cylindrical portions.

The reason for this will be apparent, for, when the diamond is dull and the cutter is traversed over the surface of the wheel, the blunt point of the diamond will, when it approaches the edge of one of the surfaces, cut into the adjacent edge of the adjacent surface so that it will not effect a sharp line of demarcation between the cylindrical and conical surfaces, and the Wheel will not have the proper profile to accurately shape the work.

The present invention is designed to prevent this inaccuracy due to the point of the cutter becoming dull, and it is contemplated that with the employment of the apparatus shown a grinding wheel may be properly and accurately dressed by a cutter, regardless of how dull the point may have become, so along as it will cut the wheel. More specifically, this result is efiected by maintaining the axis of the cutter atsubstantially right angles to the surface of the wheel upon vide an apparatus for dressing grinding wheels 2 Y which it is operating at all times during the cutting operation. In other words, when the cutter is operating on a portion of the'suriace of the grinding wheel which is parallel to the axis of the wheel, the cutter will stand at right angles to the wheel axis, but when the cutter operates upon a portion of the surface of the wheel which is'at an oblique angle to the wheel axis, the cutter will be swung pivotally through the proper angle which will position it at right angles to the surface which is to be dressed.

The surface of the grinding wheel will thus be properly dressed, and in order to accomplish this a certain amount of undercutting isrequired where a cylindrical portion of the wheel joins a frusto-conical portion. Therefore, the wheel is not dressed tothe exact form of the finished work owing to the necessity for this undercutting due to the angular relation of the diamond to the axis of the wheel. As will be hereinafter explained, this undercut, which is produced on one area of the wheel while the cutter is operating on an adjacent area, will not affect the final shape of the finished work, and this undercut will be produced whether the cutter has a sharp or blunt point.

In performing grinding operations with a wheel dressed according to the present invention, and particularly when the work is composed of cylindrical and frusto-conical portions, the work is advanced against the rotating grinding wheel until the desired dimensions have been secured, except at portions opposite the undercut zones upon the wheel at which a certain amount of surplus material will remain. The work is then moved laterally with relation to the wheel to remove this surplus stock occurring at the junction of the cylindrical and conical portions of the.

work, and thus the junction between two such portions is sharp and formed to perfect dimensions.

One object of the invention is to provide a new and'improved apparatus for dressing grinding wheels. 7

A further object of the invention is to prohaving surfaces making various angles with the axis of the wheel, whereby the cutting or dressing tool will be so controlled as to cut a true and accurate surface on the wheel regardless of whether the cutting tool may be sharp or dull.

Still another object of the invention is to provide an improved apparatus for dressing grinding wheels having a cutter mounted 'upon a carrier, and provision for traversing thecutter along the surface of the wheel as well as for permitting the carrier to swing angularly in order to maintain the axis of the cutter at right anglesto the surface of the wheel engaged by it even though certain of the surfaces upon the wheel may stand at an angle to other surfaces thereof.

To these and other ends, the invention consists in the novel features and combination of parts to, be hereinafter described and claimed herein.

In the accompanying drawings:

Fig. 1 is a front elevational view of a portion of a grinder to which my invention is applied;

Fig. 2 is a partial top plan View of the same, 7

showing the wheel dressing device;

Fig. 3 is a sectional view on line 3-.-3 of Fig. 1;

Fig. 4 is a top plan view of the dressing device with the movable carrier removed to showthe master plate;

Fig. 5 is a top plan View of the tool carrier;

Fig. 6 is. a sectional view taken on line fie-,6 of Fi Fig. 7 is a sectional view taken on line I .I of F g Fig. 8 is, an enlarged view showing the action of a grinding wheel upon a piece of work;

Fig. 9. is an enlarged fragmentary view, show.- ing the action of the cutter when the wheel is beike d ess d;

Fig. 10 is' a view similar to Fig. 5, showing a slightly modified form of cutter carrier; and

Fig. 11; is a sectional view taken on line I I ,I I Qt g- I illustrate a preferred embodiment of my invention, I have shown in Figs. 1 and 2 of the d awin a g n i i e comprising. 1 base bed I-fl; upon which is slidably mounted a work slide I ,I having thereon work-rotating mechanism t2; for; rotating the work spindle 13 to rotate the wgrk contact with the surface of 'a grinding wh el; III the wheel being rotated by suitable mechanism I 5. As will be understood by those sk ed in the. art, the foregoing elementsmay be 6i usual form, and controls I6 and IIf are provided to move the grinding wheel up to the work and for moving the slide II along the. bed.

1} stop t3 on the carriage slide cooperates with a gauge. a on the bed to set the carriage at the proper position for grinding the work, while a worlg stop or gauge IS on the carriage determines the precise positioning of the work with respect t the. grinding. wheel I4 in order that the work will begiven the proper shape or profile, The structure so far described may be that 'of the conventional grinding machine and illustrates the type of; device to which my novel structure may be applied as will now be described.

Secured to'the carriage slide I I is a base member 20. provided with an upwardly facing table 2;I surrounded by a well 22 for a sealing fluid, this well being bounded at the front of the table by. a lip 23, Rigidly mounted upon the table 2I is a master plate or matrix 24-, this plate being of the form shown in Fig. 4. As illustrated, it is provided with a recess or opening 25 at its upper su ;face, this recess being provided at each end with fingers or slots designated by the numerals 235, 2 1 28, 26?, 21?, and 28 It may also be noted that the inner. (upper as shown in Fig. 4) edges of theslots 28 and 28 are provided with stepped DQntlQnQ 2'9, and 29*. the purpose of which will be described hereinafter.

lil lounted upon the master plate 24 is a tool carrieror cutter carrier 30, this carrier having a pet leeml e endin a g d pt tqme ie gelr ing contact with the liquid in the well 22. The tool or cutter carrier 30 is freely mounted upon the plate 24 so that it may move slidably longitudinally thereof and also be moved freely transversely of the plate and also be swung rotatably to a limited extent thereon. The cutter carrier is provided with a socket 32 in which the tool 33 may be secured, this tool carrying the cutter point 34 whieh may be, the usual diamond cutter.

As illustrated, the well 22 extends entirely around the carrier 30, as also does the lip 3!. Thus the interior of the tool-carrying mechanism is sealed against the entrance of extraneous material, particularly grit, and thus undue wear on the parts, and particularly the master plate 24, is prevented. It will be understood that the level of the water or liquid within the well 22 will be maintained at a definite height, and, as shown, themaster plate is mounted above this level, but the downwardly projecting lip or skirt 3I will conac 23% uid e l n 9 33 .5 ae il i the en r nce Q extreeeq m tt t the ur ac of t e pla e RO ata Y mai e e utte ca eer 3 as s own m r es c al s esan 6 is shat- 35 suita l t a n d a ns q e edine m re.- ment, this shaft carrying a hand wheel; 36 by hi h it ma be e tted. nd b n praises ace t i s. e t a r on w th. t ea s it wmr n wi h t re d 3 Qt the s is n 38; c ried upon a 139.- pas eelvesel d nwa d y h o gh elon at d o e-t n s. i the mast P a e. a d the able- ?lhe lqwer end of th s P Q 3 up n the werd 1 9; o a l v r 4 i q e at 43 m. h rqs ahl m u ed up n, a Pi which P n. ha it e dsr qkab y mounted in brackets 46 (Fig. 7) secured to the lev side f he base m m er 2-- Th le r; 42 tend ward y th ue ste ped; ng. 4. n e ba memb and. i mi vided wi a andl r wh cht te end o t e e e y e. d pressed, thus raising the. inner end and carrying th u 38- n per v e gag m nt i h. h screw. threads 31 of the shaft 35-. The lever may then, e m ve a erally a gut q .3- o, case he s e l Wer-P of the pe i and. tha h e. the et ,8 n ised p si S tha o a on. e. Shaft 3 wi l e the u ter Pie nd; Gli er ames t ur c of the i di whe .1

Ithes .1 23 been sfiateq 2 23- h 2 1 30, is; capable of universal movement upon. the master plate 24, and it is forthis reason that the opening 40, through which passes the. pin 38, is 9.9%???1 t ansvers y of t e 13. plate. 2 a t2 pe mi e c t r a e 1 o ve r e versely to the aigis of the shaft (i5 v and still; rere n. e i re e i e b we n, t s shaf a d he l lfi; 3.8- V

Toe-s e h u e 3 2 3 in ts o emen t attes s Provided wi ownw rdl o t: nt ns 51 g? 1 on t u de ur ace h th Pins are d p ed o b dedw hin he re s es 2 3; 5 .1 a d 9* e nds. cf h openi o e s Z t l. Q i ccu se. be understood that the shape; and disposition of these guide slots in the master plate to control the movement of; the cutter carrier or tool carrier will depend upon the profile of the surface of the grinding wheel, and as will be hereinafterexplained; the particular master plate shown is so constructed as to properly guide the. cutting tool 3. dr sinea r ndi g Wh e of rm h n n Elsa and.

11 3 .9 '9: 9: EQPI QQ ma 9? RmY QQd with a micrometer gauge 52 having a plunger 53 designed to be contacted by a stop 54 attached to the carriage slide II to determine accurately the position of the tool 33 with respect to the grinding wheel 14 so that, when it is desired to dress the wheel, the slide ll may be moved to the left, as shown in Fig. 1, until the member 53 is contacted by the stop 54 and the reading of the gauge shows that the cutting tool has been brought to the proper position relatively to the grinding wheel. e

As shown in Figs. 8 and 9, the grinding whe is provided with a plurality of cylindrical zones or areas A, B, C and D, the surfaces of which are parallel to the axis of the wheel and also with frusto-conical areas E and F, the surfaces of which are inclined to the axis of the wheel and, of 'course, also inclined to the surfaces of the cylindrical zones. A workpiece 58 is shown in .Fig. 8, the workpiece in this instance being a choke member or sleeve to be applied to a gun barrel, and it will be noted that this member is provided with cylindrical zones A, B, C and D and the frusto-conical or tapered zones E" and F which are complemental to the surface of the grinding wheel.

As heretofore stated, if the grinding Wheel It were dressed by the ordinary method when the cutter becamedull, it would not dress the surface accurately adjacent the junction between the surfaces E and F and the adjacent surfaces or zones C and D. By the present invention accurate dressing of the wheel is obtained by maintaining the axis of the cutting point at right angles to the surface of the wheel being dressed at all times as shown diagrammatically at 33 33*, and 33 in Fig. 9.

When the operator of a grinding machine desires toredress the grindingwheel, the slide H is movedto the left so as to carry the work I3 away from the wheel and bring the cutting tool 33 to the proper position relatively to the wheel M. This position is determined by the reading of the gauge 52. The operator then moves the cutter carrier to the left until the pin 50 seats against the end of the slot 26 in the master plate 24. He then swings the carrier 30v until the pin 50 engages the upper edge of the slot 26 and with his hand maintains forward pressure upon the carrier 3!) so that the pins 50 and 50 will follow the. upper edges of the slots 26 and 26 vwhen the carrier is moved transversely of the grinding wheel. The operator then raises the nut 38 by pressing downwardly on the handle M of the lever 42 and moves this handle laterally in the stepped opening 41, so that the nut will be maintained in engagement with the threads 37 of shaft 35. By means of the hand wheel 36, the carrier 30 is then fed toward the left, as shown in the drawings, until the'pin 50 has reached the end of the slot 26. The surface F of the grinding wheel has been dressed by this operation, the tool being held at the angle shown in Fig. 9 at 33. When the pin 50 has reached the end of the slot 26 the nut 38 is dropped and the carrier 30 1 wheel.

In the same manner, the pins 50 and 50 ar ,then positioned in the slots 28 and 28 and the 6 tool again fed acrossthe work. .The stepped upper edges 29 and 29- of these slots cause the tool to dress the areas D, C, B and A which are of unequal radii. During thismovement the tool is maintained at. a position at right angles to the axis of the work as shown at 33 in Fig. 9.

It will be apparent that at the endsof .the movements of the tool over the surfaces F and E, small undercut corners. I l and N maybe left adjacent the zones D and C in order to prevent the tool cutting over into these zones, and, when may readily be removed, however by moving. the

.workpiece58 .to vthe left while in contact with the wheel 'after thecompletion of the rest 'of the grinding operation. This movement to the left,

as will be seen, will remove the surplus material ,at fill-andifiii and-leave the workpiece with the smooth cylindrical surfaces C and D shown in Fig. 8. a

By dressing the grinding wheel in the manner described above accurate results are always obtained and are not dependent upon the.sharpness'of thev diamond point employed. .Thus a point may be used as long as it is sharp enough to cut, and the shape and dimensions of the work produced will be the same with the last use of the point as with the first regardless of the wear to which it may have been subjected.

In Figs. 10 and 11 of the drawings I have shown a slightly modified form of my invention, particularly with respect to the pins 50 and 50. In the form of my invention previously described these pins are fixed with respect to the cutter 33. It may be, however, that in some kinds of Work the master plate will be of complex form, and it will be difficult, when the pins are fixed, to cause these pins to enter the various guiding surfaces of the plate. As shown in Fig. 11, for example, the pins 50 are set in the lower ends of plungers 61, these .plungers being slidably mounted in the upper portion of the tool carrier 30 and being releasably held in upper or lower positions by spring-pressed balls 62 engaging in upper and lower annular recesses 63 in the 'plungers 6 I. -Each of the plungers 6| may-be provided with a cap 64 by which they may be raised or depressed when desired.

Thus when it is desired to move the pins from one slot to another of the master plate the plunger 6| may be raised to raise the pins 59 out of engagement with the master plate, and the cutter carrier may then be moved to the proper position after which the pins will be lowered to a position to engage the plate. Otherwise, the

modification shown in Figs. 10 and 11 does not differ from that shown in the remaining figures of thedrawings; I

the surface of the wheel, means for varying the angle. of the path of such movement with respect vto the. wheel-axis, said means comprisinga plate 'havingan elongated opening therein, aplurality of guide slots. communicatin with said opening arcane atv each end: thereof, and said carrierbeing provided with elementsreceived: in said slots.

2. An apparatus for dressing rotatably mounted grinding wheels comprising a tool carrier, a base upon which said carrier is mounted, means: for maintaining the carrier on the base tor sliding and swinging movement thereon, a guide plate on said base, cooperating means on said: plate and carrier to guide the latter through movements in substantially rectilinear paths atdifiierent angles with respect to. the axis or thewheel being dressed, said cooperating means including-- a plurality of elements projecting from the carrier, said plate being provided with an elongated: opening therein, a plurality of guide slots communicating with said opening at each end thereof, said elements being'received in said slots, and means for securing av cutting tool to the carrier.

3'. An apparatusf or dressing rotatably mounted grinding wheels, comprising a tool carrier, 2. base upon which said carrier is mounted, means for maintaining the carrieron the base for sliding and swinging movement thereon, a guide plate on said base having a plurality or guide means to, guide said carrier in substantially.- rectilinear paths across portions: of the surface of the wheel and at diflerent angles with respect to. the axis of the wheel, said guide means inciuding a plurality: of slots.- formed in said plates certain of which extend at oblique. angles to, the of the: wheel, and an opening in said. plate with which the. innerends of said slots. communicate.

4. An apparatusfor dressing rotatably mounted grinding wheels comprising a, tool carrier, a base upon which said carrier is mounted, means: for

maintaining the carrier on the base for sliding and swinging movement, thereon, a uide plate on said base having means. for holding the carrier at various angular positions. with respect to the plate, said lastenamed means including; an elongated opening in the Plate and; a. plurality: of guide slots. communicating with said opening at each end thereof, means for movin said: carrier across; the surface of the wheel: in SuhS nii lly rectilinear paths. when so; held. and; a cu tin tool secured to the. carrier,

5'- An pp rat s; for dressin :ro a abiymeuutcd r nd n whe ls om r a o rie t as p which said arri r: ncurred, mean or restrainin the. ca r e on; he base o s id and swin in movement hereon, a ide. ate on said basehavme a p urality of rect i eareu o s; a ran ed at. d ieren a ular: eosi c thereon. a d plate. having e o ated pen n with which the, inner'ends, of saidslots communi- Qate, cooperating mean on, the carrier; to; enga e said uide. means and. estra n. the mo eme t or the carrier in p ths de rminedbr a d uid means, means to move said carrier across the surface of the wheel, and a cuttingtool; secured to the carrier.

6'. An apparatus. for dressing rotatablyfmounted grinding wheels, comprising a tool: carrie 9,, base upon. which said carrieris; mounted, means; or maintaining the carrier on the a e 9! slicin and swinging movement there0n, av guide, plate on said; base having an elongated opening therein and a plurality of guide slots, communicating with said opening at each end thereofsome of which are arranged at oblique angles to. others thereof, a cutting tool secured to. the carrier, pins on, the carrier adapted to be received: in. said slots, and means for traversing the, carrier along the plate whereby the movement of the. carrier is guided by engagements or the pins in the slots.

7-; An apparatus for dressing:rotatablymounted grinding wheels comprising a tool carrier, at base upon which said carrier is mounted, means for maintaining the carrier on the base for slidin and swinging movement thereon, a guide plate on said base having an elongated opening therein and a plurality of guide slots communicating with each opening at each end thereof, some ofwhich are arranged at oblique angles to others thereof, a cutting tool secured to the carrier, pins on the carrier adapted to be received in said slots, and means to eifect movement of the carrier with respect to the plate to cause the cutter to traverse the grinding Wheel.

8-. An apparatus for dressing rotatably mounted grinding wheels comprising a tool carrier, a base upon which said carrier is mounted, means for maintaining the carrier on the base for: sliding and swinging movement thereon, a guideplate on said base having an elongated opening therein, a plurality of guide slots communicating at their inner ends with said opening at each end thereof, some of which are arranged at oblique angles to others thereof, a cutting tool secured to the carrier, pins on the carrier adapted to be received in said slots, means to efiect movement of the carrier with respect to the plate to cause the cutter to traverse the grinding wheel, and the outer ends of said slots being closed to limit the traverse movement of the carrier.

9. An apparatus for dressing rotatably mounted grinding wheels comprising a toolcarrier, a base upon which said carrier is mounted, means for maintaining the carrier onthe base for sliding and swinging movement thereon, a guide plate on said basehaving a plurality oielongated slots therein, some of which are arranged at oblique angles to others thereof, a cutting tool secured to the carrier, pins on the carrier adapted to be received in said slots, means to effect movement of the carrier with respect tothe plate to cause the cutter to traverse the grindingwheel, said last-named means comprising a threaded. shaft rotatably carried by one of said parts, and a cooperating nut associated with the other part.

10. An apparatus for dressing rotatably mounted grinding wheels comprising a tool car-- rier, a base uponv which said carrier is mounted, means for maintaining the carrier on the base for sliding and swinging movement thereon, a guide plate on said base having a pluralityof elongated slots therein, some of which are arranged at oblique angles to others thereof; a cutting tool secured to the carrier, pins on the carrier adapted to be received in said slots, means to effect movement of the carrier with respect to the plate to cause the cutter to traverse the grinding wheel, said last-named means comprising a threaded shaft rotatably carried byone of said parts, a cooperating nut associated with the other part, and said nut being shii'table into and out of engagement with the shaft.

11. An apparatus for dressing rotatably mounted grinding wheels comprising a tool carrier, a base upon which said carrier is mounted, means for maintaining the carrier on the base for sliding and swinging movement thereon, a guide plate on' said base having a plurality of elongated slots therein, some of which are arranged at oblique angles to others thereof, a cutting tool secured to the carrier, pins on the carrier adapted to be received in said slots, means to efiect movement of the carrier with respect to the plate to cause the cutter to traverse the g-ri-nding wheel, saidlast-named means comprising a 9 threaded shaft mounted on the carrier, a nut movably associated with the plate, and means for moving said nut into and out of engagement with the shaft.

12. An apparatus for dressing rotatably mounted grinding wheels comprising a tool carrier, a base, a guide plate carried by the base upon which the tool carrier is slidably supported, means for sealing the space between the carrier and base to prevent extraneous material reaching the plate, said means comprising a liquid well provided upon the base, and a downwardly projecting flange on said carrier adapted to engage the liquid in said well.

13. An apparatus for dressing rotatably mounted grinding wheels comprising a tool carrier, a base upon which said carrier is mounted, means for maintaining the carrier on the base for sliding and swinging movement thereon, a guide plate on said base, cooperating means on said plate and carrier to guide the latter through movements in substantially rectilinear paths at different angles with respect to the axis of the wheel being dressed, said last-named means comprising a plurality of slots in said plate some of which that are arranged at oblique angles to others thereof, and an opening in said plate with which said slots communicate, means for securing a cutting tool to the carrier, and means for sealing the space between the base and carrier to prevent extraneous material entering therebetween.

14. An apparatus for dressing rotatably mounted grinding wheels comprising a tool carrier, a base upon which said carrier is mounted, means for maintaining the carrier on the base for sliding and swinging movement thereon, a guide plate on said base, cooperating means on said plate and carrier to guide the latter through movements in substantially rectilinear paths at different angles with respect to the axis of the 10 wheel being dressed, means for securing a cutting tool to the carrier, means providing a well on said base adapted to contain a liquid, and a downwardly depending flange on the carrier adapted to project into said liquid.

15. An apparatus for dressing rotatably mounted grinding wheels comprising a tool carrier, a base upon which said carrier is mounted, means for maintaining the carrier on the base for sliding and swinging movement thereon, a guide plate on said base, cooperating means on said plate and carrier to guide the latter through movements in substantially rectilinear paths at different angles with respect to the axis of the wheel being dressed, means for securing a cutting tool to the carrier, means providing a well on said base adapted to contain a liquid, and a downwardly depending flange on the carrier adapted to project into said liquid, said well and flange surrounding the carrier.

16. An apparatus for dressing rotatably mounted grinding wheels, comprising a tool carrier, a guide plate upon which said carrier is slidably mounted, means providing a well for a sealing liquid surrounding said plate, and a flange upon said carrier projecting into said liquid to prevent the entrance of extraneous matter between the carrier and plate.

EZEKIEL FIELD WHITE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,056,149 Grifllng Sept. 29, 1936 2,294,494 Wilson Sept. 1, 1942 2,304,970 Turner Dec. 15, 1942 2,313,055 De Vlieg Mar. 9, 1943 2,391,122 Bunker et a1 Dec. 18, 1945 

